1. Field of the Invention
The present invention relates to a current sensor, in particular, to a current sensor for measuring magnitude of a measured current which flows through a conductor.
2. Description of the Related Art
A conventional current sensor is provided with an annular magnetic core which has a closed magnetic path including a void in a portion thereof, and a magnetic detecting portion for detecting flux of a magnetic field generated in the void of the magnetic core (JP-A-64-83154).
The magnetic core is arranged around the conductor which carries the measured current, and is configured to focus the flux of the magnetic field generated by the measured current which flows through the conductor. The magnetic detecting portion is arranged inside the magnetic core, and is configured to output a detection signal corresponding to the flux of the magnetic field generated in the void of the closed magnetic path.
In such a current sensor, the flux of the magnetic field generated by flowing the measured current through the conductor is focused at the magnetic core, the flux of the magnetic field generated in the void of the magnetic core is detected at the magnetic detecting portion, and it is thereby possible to measure a flow rate (magnitude) of the measured current.
However, according to the current sensor described in JP-A-64-83154, in order to obtain uniform magnetic field distribution in the void of the magnetic core, the outside dimension of the magnetic core needs to be set large or it is necessary to arrange the magnetic detecting portion at a specific position. Thus, for the former, there are problems of not only an increase in the size of the entire sensor, but also of the high cost. On the other hand, for the latter, there is a problem that flexibility for arranging the magnetic detecting portion is decreased and it is thus difficult to mount the sensor.